1. Field of the Invention
The present invention generally relates to a backlight module. Particularly, the present invention relates to a light guide plate positioning design for a backlight module of a display device.
2. Description of the Prior Art
Liquid crystal display (LCD) has been extensively applied to various electronic products such as computers, televisions and mobile phones. Backlight module is one of the important components in the liquid crystal display, and the light source device used in the backlight module directly affects the performance and the assembly cost of the backlight module. Light emitting diodes (LED) become one of the light source commonly used due to its small volume and low energy consumption. In addition, the edge-lighting backlight module has received more attention compared to the bottom-lighting backlight module in virtue of its small thickness.
The usual edge-lighting backlight module includes a light source device, a light guide plate, and a support base. As FIG. 1 shows, the light guide plate 2 is positioned by the positioning pillars 4. The positioning pillar 4 positions the light guide plate 2 in order to assure a fixed relevant distance between the light guide plate and the light source device so that the structure and optical performance of the light guide plate will not be affected by high temperature of the light source device. In addition, the positioning pillars restrict degree of freedom of the light guide plate, and therefore can secure the light guide plate when performing environmental test such as impact or shock test. However, the collision between the light guide plate and the positioning pillars induced from impact or shock will result in cracks and breakage of the light guide plate. Moreover, if the strength of the positioning pillar is not strong enough, the environmental test will make the positioning pillar slant to lose the positioning function.
One conventional approach to improve the positioning ability and reduce the impact on the positioning pillar during the environmental test is usually through increasing the number of positioning pillars. However, increasing the positioning pillars also results in over restriction to degree of freedom during assembly of the light guide plate, and therefore raises difficulty in production control and test. On the other hand, increasing the positioning pillars also results in larger extent of tolerance and therefore affects the positioning function.